Go to Post SELECT YOUR STRATEGY BEFORE YOUR ROBOT DESIGN. - Kims Robot [more]
Home
Go Back   Chief Delphi > Technical > Programming > Java
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
Reply
Thread Tools Rate Thread Display Modes
  #1   Spotlight this post!  
Unread 13-01-2014, 19:13
mattachew12 mattachew12 is offline
Registered User
FRC #3597
 
Join Date: Feb 2013
Location: Maine
Posts: 20
mattachew12 is an unknown quantity at this point
Mecanum forward rotation error

We're having auto-disable troubles with our mecanum drive system. Using RobotDrive's cartesian system, we can move in the XY plane fine, and our left rotation can receive full power, but whenever we push right rotation (positive side) to 38% power, all four jaguars disable simultanously and require a disable/re-enable to work again. The ports don't matter and neither does the axis on the controller. The Jaguars are fine because they all go 100% during every other movement, just not positive rotation. Currently we have a functional robot by dividing the rotation inputs by 3 so it never hits above 33%, but I'd prefer to cure the cause rather than the symptom. I think it is a problem in RobotDrive, any ideas?
__________________
Error 404-Signature Not Found
Reply With Quote
  #2   Spotlight this post!  
Unread 13-01-2014, 22:57
shindigo shindigo is offline
Registered User
AKA: Mike Parker
FRC #0102
Team Role: Mentor
 
Join Date: Feb 2012
Rookie Year: 2009
Location: Somerville, NJ
Posts: 33
shindigo is an unknown quantity at this point
Re: Mecanum forward rotation error

I have witnessed jaguars cut out when they are under excessive load so look for something mechanical that may be causing problem with rotation in that direction. Btw, we have also found that victors do not have this problem/feature.
Reply With Quote
  #3   Spotlight this post!  
Unread 14-01-2014, 00:21
Joe Ross's Avatar Unsung FIRST Hero
Joe Ross Joe Ross is offline
Registered User
FRC #0330 (Beachbots)
Team Role: Engineer
 
Join Date: Jun 2001
Rookie Year: 1997
Location: Los Angeles, CA
Posts: 8,590
Joe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond repute
Re: Mecanum forward rotation error

I suspect that your digital sidecar isn't properly powered. It gets some power through the DB-37 cable, but not enough to send a full speed PWM to 4 motors. Assuming that your right motors are inverted in code, a left turn is minimum PWM to all motors and a right turn is full PWM to all motors.

Disconnect the DB-37 cable from the digital sidecar and make sure that all 3 power LEDs are brightly lit.
Reply With Quote
  #4   Spotlight this post!  
Unread 14-01-2014, 01:53
mmaunu's Avatar
mmaunu mmaunu is offline
Registered User
FRC #2485 (W.A.R. Lords)
Team Role: Mentor
 
Join Date: Mar 2013
Rookie Year: 2010
Location: San Diego, CA
Posts: 89
mmaunu is a jewel in the roughmmaunu is a jewel in the roughmmaunu is a jewel in the roughmmaunu is a jewel in the rough
Re: Mecanum forward rotation error

It sounds like your wheels aren't spinning in the correct directions. We had similar problems a couple of years ago. Have you inverted the motors on the left side (or right side) like Joe mentioned? This ended up being the cause of our woes; we hadn't inverted any of our motors.

First, are your wheels mounted correctly? When you look down on the robot from above, do the front rollers want to roll in towards each other when the robot moves forward? Do the back rollers want to roll away from each other? Here is a top-down view:

\.........../
\.........../
\.........../
.............
.............
/...........\
/...........\
/...........\

Put your robot up on blocks and look at the way the wheels spin (again, look from above).
1) When you direct the robot to go forward, all wheels should spin forward.
2) When you direct the robot to go backwards, all wheels should spin backwards.
3) When you direct the robot to strafe right: the right front wheel should spin towards the back of the robot, the right back wheel should spin towards the front, the left front wheel should spin forwards (towards the front), and the left back wheel should spin backwards (towards the front).
4) Test again with strafe left: left front should spin towards the rear, left rear towards the front, right front towards the front, and right rear towards the back. (The wheels diagonally across from each other should turn in the same relative direction.)
5) When you rotate clockwise, the right wheels should rotate towards the back of the robot and the left wheels should rotate towards the back of the robot. (The wheels on the same side of the robot should turn in the same direction...and each side of the robot should turn in opposite directions.)
6) When you rotate counter-clockwise, the right wheels should rotate towards the front and the left wheels should rotate towards the back.

I am not sitting in front of a robot so take those directions with a tiny grain of salt. Somebody feel free to correct me.

Again, it sounds like a symptom that we had to track down before. Try inverting the left motors but not the right (or vice-versa). This can be done in code (Java and C++ have method calls on the speed controllers and LabView allows you to set this property as well).

I hope that this helps. Mecanum is fun to drive ~(_8^()
__________________
2014 Las Vegas (Winners with 987, 2478; Excellence in Engineering)
2014 San Diego (Finalists with 987, 3250; Quality Award)
2013 Inland Empire (Winners with 1538, 968; Excellence in Engineering Award)
2013 San Diego (Finalists with 2984, 4322; Creativity Award)
2012 Las Vegas (Finalists with 2034, 3187; Quality Award)
Reply With Quote
  #5   Spotlight this post!  
Unread 14-01-2014, 09:02
mattachew12 mattachew12 is offline
Registered User
FRC #3597
 
Join Date: Feb 2013
Location: Maine
Posts: 20
mattachew12 is an unknown quantity at this point
Re: Mecanum forward rotation error

This problem is occurring even when the robot is on blocks and the wheels aren't bearing any weight, so I'm fairly sure it isn't mechanical. The wheels are in the correct configuration with the from top X from bottom O, and the signals to the wheels are all correct in regard to strafing, rotating, etc. I haven't checked the sidecar recently but we have been having troubles with those lights. We already switched out one sidecar because of it. Any ideas what can be done to keep that part of it from breaking? I noticed on tank drive that this also happens in one specific scenario, when all four motors are putting out negative power and more than two go above the 38%, which even though we have positive axis rotation on mecanum the jags are also putting out four negative signals.
__________________
Error 404-Signature Not Found
Reply With Quote
  #6   Spotlight this post!  
Unread 16-01-2014, 19:28
mattachew12 mattachew12 is offline
Registered User
FRC #3597
 
Join Date: Feb 2013
Location: Maine
Posts: 20
mattachew12 is an unknown quantity at this point
Re: Mecanum forward rotation error

Update: We've isolated the problem to the lights on the sidecar. Something is breaking the 6V light. Every time this disable problem happens the sidecar's 6V light is off. When we switched a new sidecar in, the three lights turned on and we got our full rotation functionality back, but today we just broke the light again by rotating too much apparently and somehow overloaded the sidecar. It auto-disabled again and now the 6V light won't come on again. What I don't get is jaguars shouldn't be affected by the 6V since their PWMs use 5V.
What breaks a sidecar's 6V capability?
__________________
Error 404-Signature Not Found
Reply With Quote
  #7   Spotlight this post!  
Unread 16-01-2014, 19:38
Joe Ross's Avatar Unsung FIRST Hero
Joe Ross Joe Ross is offline
Registered User
FRC #0330 (Beachbots)
Team Role: Engineer
 
Join Date: Jun 2001
Rookie Year: 1997
Location: Los Angeles, CA
Posts: 8,590
Joe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond repute
Re: Mecanum forward rotation error

Quote:
Originally Posted by mattachew12 View Post
Update: We've isolated the problem to the lights on the sidecar. Something is breaking the 6V light. Every time this disable problem happens the sidecar's 6V light is off. When we switched a new sidecar in, the three lights turned on and we got our full rotation functionality back, but today we just broke the light again by rotating too much apparently and somehow overloaded the sidecar. It auto-disabled again and now the 6V light won't come on again. What I don't get is jaguars shouldn't be affected by the 6V since their PWMs use 5V.
What breaks a sidecar's 6V capability?
The only thing that uses 6v is servos (when the jumper is installed next to the PWM). I suspect that you are not getting power to the digital sidecar. Did you remove the DB-37 cable and look at the LEDs like was suggested earlier?
Reply With Quote
  #8   Spotlight this post!  
Unread 16-01-2014, 19:48
mattachew12 mattachew12 is offline
Registered User
FRC #3597
 
Join Date: Feb 2013
Location: Maine
Posts: 20
mattachew12 is an unknown quantity at this point
Re: Mecanum forward rotation error

Quote:
Originally Posted by Joe Ross View Post
The only thing that uses 6v is servos (when the jumper is installed next to the PWM). I suspect that you are not getting power to the digital sidecar. Did you remove the DB-37 cable and look at the LEDs like was suggested earlier?
When we take off the cable the 5V and RSL lights turn off. What should happen?
__________________
Error 404-Signature Not Found
Reply With Quote
  #9   Spotlight this post!  
Unread 16-01-2014, 19:50
Ether's Avatar
Ether Ether is offline
systems engineer (retired)
no team
 
Join Date: Nov 2009
Rookie Year: 1969
Location: US
Posts: 8,102
Ether has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond repute
Re: Mecanum forward rotation error

Quote:
Originally Posted by mattachew12 View Post
When we take off the cable the 5V and RSL lights turn off. What should happen?
How are you powering the sidecar?


Reply With Quote
  #10   Spotlight this post!  
Unread 16-01-2014, 19:55
mattachew12 mattachew12 is offline
Registered User
FRC #3597
 
Join Date: Feb 2013
Location: Maine
Posts: 20
mattachew12 is an unknown quantity at this point
Re: Mecanum forward rotation error

Quote:
Originally Posted by Ether View Post
How are you powering the sidecar?
We have the DB-37 cable attached as well as a WAGO connecting to the PD board with a 20A fuse.
__________________
Error 404-Signature Not Found
Reply With Quote
  #11   Spotlight this post!  
Unread 16-01-2014, 19:56
Joe Ross's Avatar Unsung FIRST Hero
Joe Ross Joe Ross is offline
Registered User
FRC #0330 (Beachbots)
Team Role: Engineer
 
Join Date: Jun 2001
Rookie Year: 1997
Location: Los Angeles, CA
Posts: 8,590
Joe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond repute
Re: Mecanum forward rotation error

Quote:
Originally Posted by mattachew12 View Post
When we take off the cable the 5V and RSL lights turn off. What should happen?
They should remain on. Did you wire the digital sidecar per the wiring diagram? http://www.usfirst.org/sites/default...icalLayout.pdf
Reply With Quote
  #12   Spotlight this post!  
Unread 16-01-2014, 19:57
Joe Ross's Avatar Unsung FIRST Hero
Joe Ross Joe Ross is offline
Registered User
FRC #0330 (Beachbots)
Team Role: Engineer
 
Join Date: Jun 2001
Rookie Year: 1997
Location: Los Angeles, CA
Posts: 8,590
Joe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond repute
Re: Mecanum forward rotation error

Quote:
Originally Posted by mattachew12 View Post
We have the DB-37 cable attached as well as a WAGO connecting to the PD board with a 20A fuse.
If the lights went out, and you are wired to the PD with a 20A fuse, there is a problem with that connection. Maybe one of the wagos is crimped on insulation rather then bare wire.

Last edited by Joe Ross : 16-01-2014 at 20:00.
Reply With Quote
  #13   Spotlight this post!  
Unread 16-01-2014, 19:58
Ether's Avatar
Ether Ether is offline
systems engineer (retired)
no team
 
Join Date: Nov 2009
Rookie Year: 1969
Location: US
Posts: 8,102
Ether has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond repute
Re: Mecanum forward rotation error

Quote:
Originally Posted by mattachew12 View Post
We have the DB-37 cable attached as well as a WAGO connecting to the PD board with a 20A fuse.
Like this?
Attached Thumbnails
Click image for larger version

Name:	DSC power.png
Views:	24
Size:	80.7 KB
ID:	15847  
Reply With Quote
  #14   Spotlight this post!  
Unread 16-01-2014, 20:00
mattachew12 mattachew12 is offline
Registered User
FRC #3597
 
Join Date: Feb 2013
Location: Maine
Posts: 20
mattachew12 is an unknown quantity at this point
Re: Mecanum forward rotation error

Quote:
Originally Posted by Joe Ross View Post
They should remain on. Did you wire the digital sidecar per the wiring diagram? http://www.usfirst.org/sites/default...icalLayout.pdf
Yes we have, the square white connector is plugged in to the DSC under the (-) and (+) symbols, and the red is with + and black with -. They are plugged into the PD board under a 30A slot with a 20A fuse.
__________________
Error 404-Signature Not Found
Reply With Quote
  #15   Spotlight this post!  
Unread 16-01-2014, 20:04
Ether's Avatar
Ether Ether is offline
systems engineer (retired)
no team
 
Join Date: Nov 2009
Rookie Year: 1969
Location: US
Posts: 8,102
Ether has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond repute
Re: Mecanum forward rotation error

Quote:
Originally Posted by mattachew12 View Post
We have the DB-37 cable attached as well as a WAGO connecting to the PD board with a 20A fuse.
Have you checked the fuse?


Reply With Quote
Reply


Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 13:17.

The Chief Delphi Forums are sponsored by Innovation First International, Inc.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi